How long does sunscreen last after opening? Reading the jar symbol and spotting a bottle that’s past it

The tiny open jar printed on the back of a sunscreen tube, with a number and the letter M beside it, tells you how many months the formula stays reliable once you’ve broken the seal. A “12M” means the product is good for 12 months after you first open it. Not from the day you bought it, and not from the start of summer.

Sunscreen generally lasts 6 to 12 months after opening.

The symbol is called Period After Opening, or PAO. Some products carry a printed expiration date instead, and if a sunscreen has both a PAO symbol and an expiration date, you follow whichever comes first. Some brands skip the date entirely: NIVEA sun creams, for instance, carry only a period of validity after opening. Franchement, the jar is the more honest of the two, because it measures the clock that matters, the one that starts when air, fingers and heat get in.

Why so many American bottles have no jar

The symbol is a familiar sight on European labels, but U.S. packaging plays by different rules. FDA regulations require sunscreens to carry an expiration date, unless stability testing has shown the product stays stable for three years. A bottle with no date is therefore assumed to last up to three years unopened, and it may show no jar either.

Finding the date can be a small scavenger hunt. The FDA sets no formatting parameters for dates, according to dermatologist Dr. Engleman. It might sit on the bottom of the bottle, on the cap, embossed on the top seal, on the crimp of a tube, or beside the barcode.

No date anywhere? Mark your purchase date on the package yourself.

Here is the part that surprises people. A printed date is less decisive than you’d think. Susan Booth, who oversees Consumer Reports’ sunscreen testing, says a sunscreen that expires in six months should work as well as one with three years left. The exception is a bottle that has been baked, since sunscreen exposed to direct sunlight or excessive heat can deteriorate faster. Once a bottle is open, some dermatologists go further and say to throw away any bottle open longer than 12 months, even if it looks normal.

What a tired sunscreen looks, smells and feels like

Your senses catch most of it. A watery consistency, separation, lumps or little pebbles, and graininess or grittiness are telltale signs a sunscreen has expired. The formula is losing its structure, and the UV filters are no longer spread evenly across your skin.

Color and scent count too. Most sunscreens are white or a light cream color, so a yellowish or browning tint is a red flag, and an odor that seems “off” means it’s probably time to ditch it.

An expired bottle may still protect a little, just not predictably.

Heat deserves its own paragraph, because it quietly ruins more bottles than the calendar does. A tube left in a hot car or on a sunny towel can lose strength before its date, as Dr. Garshick notes. That beach-bag bottle from July, the one that rode around in the trunk, is the most suspect one you own.

Making a bottle last exactly as long as it should

Write the opening date on the bottle with a permanent marker, the day you break the seal. Keep it somewhere cool and dark, and remember that heat and humidity can speed up breakdown.

The surprising upside of proper use is that you’ll rarely see a bottle age out. The American Academy of Dermatology recommends about one ounce for the body, roughly two tablespoons or a shot glass. For the face, ears and neck, use the “two-finger method.” At that dose, a bottle empties in a handful of beach days, long before any jar symbol comes into play.

Here is a nuance that Matters More Than any date. Reapply about every two hours, more often if you’re swimming or sweating. A fresh, in-date bottle applied thinly and once will still leave you burned.

Sources : oreateai.com | aol.com